Synthesizers use various methods to generate electronic signals. Among the most popular waveform synthesis techniques are subtractive synthesis, additive synthesis, wavetable synthesis, frequency modulation synthesis, phase distortion synthesis, physical modeling synthesis and sample-based synthesis. Other less common synthesis types include sub harmonic synthesis, a form of additive synthesis via sub harmonics, and granular synthesis. None of these waveform synthesis techniques provide phase coherent wave switching at audio rate.
Therefore, there is an unfulfilled need for a better way of controlling switching periods thus allowing for a greater and more dynamic number of waveform variations, better synchronous musical relationships between the switch and the source oscillators, and allowing for complex sounds and harmonics to be created.